A kerosene-fueled X-33 as a single stage to orbit vehicle.
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From: J. Clarke on 11 Apr 2010 14:57 On 4/11/2010 1:59 PM, Matt wrote: > On Sun, 11 Apr 2010 10:28:48 -0700 (PDT), hcobb wrote: > >> On Apr 10, 8:29 am, Robert Clark<rgregorycl...(a)yahoo.com> wrote: >>> Note also that use of the rocket thrust from the X-33 would also allow >>> you to reach higher speeds say Mach 3+ before release. This would >>> allow greater payload, since less delta-V would need to be supplied by >>> the X-33 after release. The extra rocket propellant for the X-33 >>> required for firing during the linked portion of the trip would be >>> carried in the carrier craft fuselage. >>> >>> Bob Clark >> >> Since you need to reach Mach 25+ to orbit this saves you only 12% of >> the speed requirement while imposing a requirement for an airframe >> that can at least sustain that ground velocity while climbing. >> >> A much better result can be had from a balloon-assisted launch system >> where the objective is to start the rocket with as much altitude as >> possible rather than speed. >> >> http://academy.grc.nasa.gov/y2008/group-project/proposal-for-a-balloon-assisted-launch-system > > This is a proposal from 2008. Was it approved? That's not a "proposal", it's a student exercise. Google "Glenn Academy".
From: Matt on 11 Apr 2010 15:21 On Sun, 11 Apr 2010 14:57:00 -0400, J. Clarke wrote: >On 4/11/2010 1:59 PM, Matt wrote: >> On Sun, 11 Apr 2010 10:28:48 -0700 (PDT), hcobb wrote: >> >>> On Apr 10, 8:29 am, Robert Clark<rgregorycl...(a)yahoo.com> wrote: >>>> Note also that use of the rocket thrust from the X-33 would also allow >>>> you to reach higher speeds say Mach 3+ before release. This would >>>> allow greater payload, since less delta-V would need to be supplied by >>>> the X-33 after release. The extra rocket propellant for the X-33 >>>> required for firing during the linked portion of the trip would be >>>> carried in the carrier craft fuselage. >>>> >>>> Bob Clark >>> >>> Since you need to reach Mach 25+ to orbit this saves you only 12% of >>> the speed requirement while imposing a requirement for an airframe >>> that can at least sustain that ground velocity while climbing. >>> >>> A much better result can be had from a balloon-assisted launch system >>> where the objective is to start the rocket with as much altitude as >>> possible rather than speed. >>> >>> http://academy.grc.nasa.gov/y2008/group-project/proposal-for-a-balloon-assisted-launch-system >> >> This is a proposal from 2008. Was it approved? > >That's not a "proposal", it's a student exercise. Google "Glenn Academy". http://academy.grc.nasa.gov/y2007/research-projects/group-project-proposal Goals in Project Choice + Useful to NASA It would appear that NASA approved the choice of the project topic. Did the "proposal" not receive some level of review within NASA? Else it was simply a time-wasting exercise. Perhaps consistent with the environment, but that's another issue. The claim in the post above was: "A much better result can be had from a balloon-assisted launch system" Has *anyone* demonstrated that it is "better," student or otherwise?
From: hcobb on 11 Apr 2010 16:42 On Apr 11, 12:21 pm, Matt <30d...(a)net.net> wrote: > On Sun, 11 Apr 2010 14:57:00 -0400, J. Clarke wrote: > >On 4/11/2010 1:59 PM, Matt wrote: > >> On Sun, 11 Apr 2010 10:28:48 -0700 (PDT), hcobb wrote: > > >>> On Apr 10, 8:29 am, Robert Clark<rgregorycl...(a)yahoo.com> wrote: > >>>> Note also that use of the rocket thrust from the X-33 would also allow > >>>> you to reach higher speeds say Mach 3+ before release. This would > >>>> allow greater payload, since less delta-V would need to be supplied by > >>>> the X-33 after release. The extra rocket propellant for the X-33 > >>>> required for firing during the linked portion of the trip would be > >>>> carried in the carrier craft fuselage. > > >>>> Bob Clark > > >>> Since you need to reach Mach 25+ to orbit this saves you only 12% of > >>> the speed requirement while imposing a requirement for an airframe > >>> that can at least sustain that ground velocity while climbing. > > >>> A much better result can be had from a balloon-assisted launch system > >>> where the objective is to start the rocket with as much altitude as > >>> possible rather than speed. > > >>>http://academy.grc.nasa.gov/y2008/group-project/proposal-for-a-balloo.... > > >> This is a proposal from 2008. Was it approved? > > >That's not a "proposal", it's a student exercise. Google "Glenn Academy". > > http://academy.grc.nasa.gov/y2007/research-projects/group-project-pro... > Goals in Project Choice > + Useful to NASA > > It would appear that NASA approved the choice of the project topic. > Did the "proposal" not receive some level of review within NASA? Else > it was simply a time-wasting exercise. Perhaps consistent with the > environment, but that's another issue. > > The claim in the post above was: "A much better result can be had from > a balloon-assisted launch system" > > Has *anyone* demonstrated that it is "better," student or otherwise? "however, no end product is currently capable of orbit insertion using this method." The F-22A had to go through a special testing procedure to clear it to lob bombs supersonically, which is far less demanding than dropping a manned launch vehicle at Mach 3. The closest thing to either method is the Virgin Galactic mission profile which gets a subsonic aircraft to fly as high as possible for a sub-orbital launch. As I've noted before if you use something other than a chemical rocket to stage up from there you can get into LEO or all the way to Mars. (Getting much further than Mars in a manned mission is going to take a bit more than 60 km/s impactors.) -HJC
From: J. Clarke on 11 Apr 2010 18:34 On 4/11/2010 3:21 PM, Matt wrote: > On Sun, 11 Apr 2010 14:57:00 -0400, J. Clarke wrote: > >> On 4/11/2010 1:59 PM, Matt wrote: >>> On Sun, 11 Apr 2010 10:28:48 -0700 (PDT), hcobb wrote: >>> >>>> On Apr 10, 8:29 am, Robert Clark<rgregorycl...(a)yahoo.com> wrote: >>>>> Note also that use of the rocket thrust from the X-33 would also allow >>>>> you to reach higher speeds say Mach 3+ before release. This would >>>>> allow greater payload, since less delta-V would need to be supplied by >>>>> the X-33 after release. The extra rocket propellant for the X-33 >>>>> required for firing during the linked portion of the trip would be >>>>> carried in the carrier craft fuselage. >>>>> >>>>> Bob Clark >>>> >>>> Since you need to reach Mach 25+ to orbit this saves you only 12% of >>>> the speed requirement while imposing a requirement for an airframe >>>> that can at least sustain that ground velocity while climbing. >>>> >>>> A much better result can be had from a balloon-assisted launch system >>>> where the objective is to start the rocket with as much altitude as >>>> possible rather than speed. >>>> >>>> http://academy.grc.nasa.gov/y2008/group-project/proposal-for-a-balloon-assisted-launch-system >>> >>> This is a proposal from 2008. Was it approved? >> >> That's not a "proposal", it's a student exercise. Google "Glenn Academy". > > http://academy.grc.nasa.gov/y2007/research-projects/group-project-proposal > Goals in Project Choice > + Useful to NASA > > It would appear that NASA approved the choice of the project topic. Just as any teacher approves the choice of the topic of term papers and other student projects. > Did the "proposal" not receive some level of review within NASA? The same review that any educational project gets. > Else it was simply a time-wasting exercise. By that logic all education is "a time wasting exercise". The purpose of education is not to come up with wonderful new ways of doing things, it's to teach students what we already know. > Perhaps consistent with the > environment, but that's another issue. The environment is a summer training program for college students. > The claim in the post above was: "A much better result can be had from > a balloon-assisted launch system" > > Has *anyone* demonstrated that it is "better," student or otherwise? Not that I know of. Useful for some purposes, probably, but superior for general use, no.
From: hcobb on 11 Apr 2010 22:32
On Apr 11, 3:34 pm, "J. Clarke" <jclarke.use...(a)cox.net> wrote: > On 4/11/2010 3:21 PM, Matt wrote: > > The claim in the post above was: "A much better result can be had from > > a balloon-assisted launch system" > > > Has *anyone* demonstrated that it is "better," student or otherwise? > > Not that I know of. Useful for some purposes, probably, but superior > for general use, no. Because we're still on the glide path from the boost that manned spaceflight got from the ICBM programs. -HJC |